A sand spreading unit used for emergency sanding of icy surfaces traveled by vehicles, particularly bridges which freeze before roadways as the temperature is close to freezing and dropping.
In parts of the USA where ice occurs on roadways, and when temperatures are close to the freezing mark, substantial problems are encountered across bridge decks which will freeze and form icy surfaces before the rest of the roadway. This freezing can occur suddenly, without warning, and cause numerous accidents. While sand and salt trucks can alleviate this situation, it is impossible to have trucks that will be immediately available in all areas.
Sand distributing devices which spread sand to improve traction are known, in particular vehicle sanding attachments. For example, U.S. Pat. No. 4,968,069 shows a sand dispensing device which is mounted onto a vehicle so that it will provide sand beneath the wheels of the individual vehicle. The unit is operated with air pressure from an electric air compressor wherein the air entrains the sand and directs it under the wheels. However, the individual sanders have not filled the need for rapid, emergency standby sanding of surfaces such as bridge decks that ice quickly and before the rest of the roadway.